1. Field of the Invention
The present invention relates generally to a gas pressure accumulating and supplying device for use in model guns, and more particularly, to an improvement in a gas pressure accumulating and supplying device having a case member which can be held detachably in a model gun and in which a pressure accumulating chamber is provided to be partitioned into a main chamber which is charged with liquefied gas injected therein through a gas injection opening and a subchamber connected with a gas discharging passage.
2. Description of the Prior Art
There has been proposed a model gun which is often called an air soft gun and provided therein such an arrangement that gas pressure is used for shooting a sham bullet put in a bullet holding chamber positioned just at the back of a barrel. In the model gun in which the gas pressure is used for shooting the sham bullet, a gas pressure accumulating and supplying block having therein a pressure accumulating chamber which is charged with liquefied gas and a gas passage for supplying a pressure chamber formed in a body of the model gun with gas pressure produced by the liquefied gas in the pressure accumulating chamber, is inserted into a grip provided in the body of the model gun. The gas pressure supplied from the pressure accumulating chamber through the gas pressure to the pressure chamber is caused to act on the sham bullet put in the bullet holding chamber so as to shoot the sham bullet in response to the movement of a trigger provided in the body of the model gun.
It has been also proposed a model gun in which gas pressure is used for supplying a bullet holding chamber provided in a body of the model gun with a sham bullet and further for shooting the sham bullet put in the bullet holding chamber, as shown in, for example, Japanese utility model application published before examination under publication number 5-8252. In the model gun thus proposed, a gas pressure accumulating and supplying block (referred to as "a magazine" in the above mentioned publication) which has a case member in which a pressure accumulating chamber in which liquefied gas is injected through a gas introducing pipe connected with a gas injecting opening, a gas discharging passage extending from the pressure accumulating chamber, a control valve for controlling the gas discharging passage to be open and closed selectively in response to the movements of a trigger, and a magazine portion for containing sham bullets are provided, is held detachably in a grip formed in a body of the model gun. Further, a cylinder chamber in which a piston rod is put is positioned to face to a bullet holding chamber provided in the body of the model gun. The piston in the cylinder chamber is moved by gas pressure supplied from the pressure accumulating chamber through the gas discharging passage made open by the control .valve to the cylinder chamber so as to shoot a sham bullet put in the bullet holding chamber and further to supply the bullet holding chamber from which the sham bullet has been shot with a new sham bullet discharged from the magazine portion, so that a plurality of sham bullets can be continuously shot automatically.
The model gun in which the gas pressure discharged from the pressure accumulating chamber provided in the case member of the gas pressure accumulating and supplying block held in the grip is used for shooting the sham bullet put in the bullet holding chamber and for supplying the bullet holding chamber with the sham bullet, as described above, is handled to cause the gas pressure accumulating and supplying block to assume such a posture that the gas injecting opening is positioned above the pressure accumulating chamber and the gas introducing pipe extends vertically downward from the gas injecting opening when the pressure accumulating chamber provided in the gas pressure accumulating and supplying block is charged with liquefied gas. With this posture of the gas pressure accumulating and supplying block, the liquefied gas injected from the gas injecting opening positioned above the pressure accumulating chamber through the gas introducing pipe into the pressure accumulating chamber can be impounded to have its surface by which the end portion of the gas introducing pipe is closed. That is, the liquefied gas is impounded at its maximum in the pressure accumulating chamber when the end portion of the gas introducing pipe is closed by the surface of the liquefied gas in the pressure accumulating chamber.
As to the model gun in which the pressure accumulating chamber provided in the case member of the gas pressure accumulating and supplying block is thus charged with the liquefied gas, it is desired that gas pressure discharged from the pressure accumulating chamber is kept at such an appropriate value that an automatic operation for shooting a plurality of sham bullets continuously is properly performed over a relatively long period. Therefore, the gas pressure accumulating and supplying block having the case member in which the the pressure accumulating chamber is provided is desired to be maintained in a condition wherein only gas obtained by evaporation of the liquefied gas in the pressure accumulating chamber is supplied through the gas discharging passage to a pressure chamber formed in the body of the model gun whenever the gas discharging passage is made open.
However, when the model gun in which the case member of the gas pressure accumulating and supplying block is held in the grip is actually used, the case member of the gas pressure accumulating and supplying block is caused to assume various postures in accordance with various kinds of handling of the model gun and the liquefied gas in the pressure accumulating chamber provided in the gas pressure accumulating and supplying block moves very actively, so that it is feared that the liquefied gas in the pressure accumulating chamber leaks out frequently to the gas discharging passage. In the case where the gas discharging passage to which a relatively large amount of liquefied gas has been leaked out from the pressure accumulating chamber is made open, the relatively large amount of liquefied gas in the gas discharging passage blows off from the gas pressure accumulating and supplying block into the body of the model gun.
This means that a situation in which the gas pressure accumulating and supplying block is not maintained in the condition wherein only gas obtained by evaporation of the liquefied gas in the pressure accumulating chamber is supplied through the gas discharging passage to the pressure chamber formed in the body of the model gun can arise when the gas discharging passage is made open. In the case where such a situation arises, the liquefied gas impounded in the pressure accumulating chamber is wasted and therefore gas pressure discharged from the pressure accumulating chamber cannot be kept at the appropriate value over a relatively long period after the pressure accumulating chamber is charged at its maximum with the liquefied gas.